Scanner comprising a light conducting element leading to a photocell remote from the optic axis

ABSTRACT

A reflex scanner is disclosed having a lens system with at least one lens by which light is directed against a target area and reflected back through the lens system and with a second lens focusing reflected light on one end of a light-conducting element whose other end is optically coupled to a light sensor.

United States Patent I I l Inventor Donald J. Matsas l2 Carpenter Road,Wayland, Man. ("778 Appl. No. Filed Patented ti77,l l4 Nov. 17, 1969June 8, 1971 ELEMENT LEADING TO A PHOTOCELL REMOTE FROM THE OPTIC AXIS14 Claims, 3 Drawing Figs.

U.S. Cl 250/227, 250/239 Int. Cl G02b 5/14, HOlj 5/02 HOlj 39/12 Fleldol Search 250/239, 227, 216

IllIIIIIIIII'IIIJI'II'I'II,

[56] Relerences Cited UNITED STATES PATENTS 3,247,391 4/1966 Ogle etal.... 250/239X 3,3 34,236 8/1967 Bacon 250/227X Primary Examiner.lamesW. Lawrence Assistant Examiner-T. N. Grigsby AttorneyAbbott SpearPATENTED JUN 8 ISYI 1221912123212 Do J1 Maison,

SCANNER COMPRISING A LIGHT CONDUCTING ELEMENT LEADING TO A PHOTOCELLREMOTE FROM THE OPTIC AXlS The present invention relates to reflexscanners utilizing light-conducting elements to transmit reflected lightto the light sensing means.

A reflex scanner has a housing provided with a lens through which lightfrom a source within the housing is directed to a target. A beam oflight is reflected from the target back through the lens to a sensor. Inone type of scanner, a mirror is interposed between the lens and thelight source to direct the reflected light beam to the sensor which islocated outside the optical axis. The lens system may provide that theemitted light is collimated or that it is focused on a small area closeto the scanner.

While such scanners have proved satisfactory for some pur poses, theyhave objectionable features limiting their utility. An objection commonto reflex scanners of all previous types is that the transmission ofreflected light to the light sensor required a relatively large objectin the light path between the light source and the lens. ln addition,increased efficiency in the system for transmitting reflected light andscanners of sizes smaller than are presently available are oftendesired.

The principal objective of the present invention is to provide a reflexscanner overcoming such objections, an objective attained by providingit with a coaxial lens system with a first lens controlling emittedlight and a second lens focusing reflected light on one end of alight-conducting element having its other end optically connected to thelight sensor. As the cross sectional area of the light-conductingelement determines the field of view of the means sensing reflectedlight, the elements may be small ranging upward from one mil in diameterwith those in the order of 0.030 inch providing satisfactory results formost uses.

Other objective of the invention are concerned with structural featuresensuring simplicity of construction and the accurate registering of thelight and optical axes and the accurate positioning of thelightconducting element with one end at the focal point of the secondlens.

In the accompanying drawings, there is shown an embodiment of theinvention illustrative of these and other of its objectives, novelfeatures, and advantages. ln the drawings:

FlG. 1 is a front view of a reflex scanner in accordance with theinvention;

FlG. 2 is a section, on a substantial increase in scale, takenapproximately along the indicated lines 2-2 of F l0. 1; and

F16. 3 is a fragmentary view, on the scale of FIG. 2, illustrating alens system in accordance with another embodiment of the invention. Thereflex scanner shown in the drawings consists of a housing 5 providedwith a removable back 6 and having an opening 7 in it front wall for aholder 8 for the lens system and having an outer plain glass window 9protecting the lens system which comprises planoconvex lenses 10 and 11having their plane faces joined together in mutual contact with a commonoptical axis and with the lens 11 substantially smaller than the lens10.

Within the housing 5 there is a bracket 12 to which a bracket 13 isconnected by means of a screw 14 passing through an oversize hole 15 inthe bracket 13 and threaded through the bracket 12. The bracket 13supports a holder 16 in which is clamped a low voltage lamp 17positioned at the focal point of the lens 10 which projects collimatedlight rays to a target area with the described connection between thebrackets permitting such horizontal and vertical adjustments of theposition of the lamp 17 as are necessary to ensure its proper alignmentwith the lens 10.

A bracket 18 within the housing 5 supports a chamber 19 for the holder20 of a light sensitive cell 21 held in a selected vertical position bymeans of a set screw 22. A light-conducting element, generally indicatedat 23, has one end passing through a hole in the chamber 19 andoptically coupled to the cell 21 and its other end at the focal point ofthe lens 11. The

end of the element 23 that is supported by the chamber 19 is lockedthereto by a set screw 24 when it has been adjusted to position itsother end at the focal point of the lens 11. The element 23 may be aquartz or clear-plastic rod, or, as shown, it may consist of one or morelight-conducting flexible fibers 25 encased in a tubular metal jacket26.

The circuit leads 27 and 28 for the lamp 17 and the circuit leads 29 and30 for the cell 21 are combined in a cable 31 secured to the housing 5by a conventional strain relieving connection 32.

The lens system of the reflex scanner just described provides for theillumination of the target area with a collimated light ray. Where asmall object is to be detected, the lens system shown in FIG. 3 is used.ln that system, the holder 7 is replaced by the holder 33 in whichplanoconvex lens 34 and 35 are supported with their plane facesproximate and spaced apart to focus the light on a small spot close tothe scanner. The lens 35 has the plane surface of a smaller planoconvexI lens 11A secured to its plane surface, the function of the lens 11Abeing the same as that of the lens 11.

As stated, the cross-sectional area of the light-conducting element 23determines the field of view of the light sensor 21 and such dimensionsmay range upwardly from one mil with an element diameter in theneighborhood of 0.030 inch providing a satisfactory field of view for awide range of uses. It will be apparent that with the small diameter ofthe light-conducting element and its support by a portion remote fromthe optical axis, the desired objectives are attained with increasedefficiency of light transmission, with a scanner construction enablingthem to be made in such small sizes that they may be installed wherespace restrictions are severe, and with the construction enabling thefield of view of the light-sensing means to be within a suitably widerange with the size of the article to be detected being limited only bythe sensitivity of the light sensing means.

I claim:

1. In a reflex scanner, a light source, a coaxial lens system includinga first lens for directing a beam of light from said source to a targetarea and focused on said light source, means to sense light reflectedfrom said area, said means including a light-conducting element disposedwith one end portion coaxial with nand located between the light sourceand said first lens and its other end portion extending into an arearemote from the path of light between the source and said first lens,light responsive means optically coupled to said last named end portion,means supporting said element and attached to a portion thereof otherthan its first named end portion and said lens system including a secondlens between said first lens and said light source and providing aconverging beam of reflected light focused on the first-named elementend.

2. The reflex scanner of claim 1 in which the first and second lensesare planoconvex and are assembled with their plane surfaces in mutualcontact, the second lens being smaller than the first lens.

3. The reflex scanner of claim 2 in which the lens system includes athird planoconvex lens arranged an disposed to provide a focal point foremitted light near the scanner, the first lens being a collimator.

4. The reflex scanner of claim 1 in which the light-conducting elementis rigid.

5. The reflex scanner of claim 4 in which the light-conducting elementis at least 1 mil in diameter.

6. The reflex scanner of claim 4 in which the light-conducting elementis in the neighborhood of 0.030 inch in diameter.

6. The reflex scanner of claim 4 in which the light-conducting elementcomprises at least one flexible light-conducting fiber and a metaljacket therefor.

8. The reflex scanner of claim 4 in which the element is adjustablerelative to its supporting means.

9. The reflex scanner of claim 4 in which the end portions of theelement are angularly disposed.

10. The reflex scanner of claim 1 and a housing in which the lenssystem, lamp, and the means in support of the light-conducting elementare mounted.

11. The reflex scanner of claim in which a chamber is supported withinthe housing, the light sensor is within the chamber and the second namedend of the light-conducting element extends into and is supported by thechamber.

12. The reflex scanner of claim ll in which the second namedlight-conducting element end is rotatably and vertically adjustable.

13. The reflex scanner of claim 12 in which the light sensor

1. In a reflex scanner, a light source, a coaxial lens system includinga first lens for directing a beam of light from said source to a targetarea and focused on said light source, means to sense light reflectedfrom said area, said means including a light-conducting element disposedwith one end portion coaxial with nand located between the light sourceand said first lens and its other end portion extending into an arearemote from the path of light between the source and said first lens,light responsive means optically coupled to said last named end portion,means supporting said element and attached to a portion thereof otherthan its first named end portion and said lens system including a secondlens between said first lens and said light source and providing aconverging beam of reflected light focused on the first-named elementend.
 2. The reflex scanner of claim 1 in which the first and secondlenses are planoconvex and are assembled with their plane surfaces inmutual contact, the second lens being smaller than the first lens. 3.The reflex scanner of claim 2 in which the lens system includes a thirdplanoconvex lens arranGed an disposed to provide a focal point foremitted light near the scanner, the first lens being a collimator. 4.The reflex scanner of claim 1 in which the light-conducting element isrigid.
 5. The reflex scanner of claim 4 in which the light-conductingelement is at least 1 mil in diameter.
 6. The reflex scanner of claim 4in which the light-conducting element is in the neighborhood of 0.030inch in diameter.
 6. The reflex scanner of claim 4 in which thelight-conducting element comprises at least one flexiblelight-conducting fiber and a metal jacket therefor.
 8. The reflexscanner of claim 4 in which the element is adjustable relative to itssupporting means.
 9. The reflex scanner of claim 4 in which the endportions of the element are angularly disposed.
 10. The reflex scannerof claim 1 and a housing in which the lens system, lamp, and the meansin support of the light-conducting element are mounted.
 11. The reflexscanner of claim 10 in which a chamber is supported within the housing,the light sensor is within the chamber and the second named end of thelight-conducting element extends into and is supported by the chamber.12. The reflex scanner of claim 11 in which the second namedlight-conducting element end is rotatably and vertically adjustable. 13.The reflex scanner of claim 12 in which the light sensor and thelight-conducting element are vertically adjustable as a unit.
 14. Thereflex scanner of claim 10 in which bracket means in the housing supportthe light source and are universally adjustable in a transverse verticalplane to ensure registry of the light and optical axes.